Water leak detector device and leak detection procedure

ABSTRACT

A device is produced as a small sphere with neutral buoyancy, within which there is, at least, one hydrophone that is connected to a signal processor, which stores the information on a memory card and that is powered by at least one battery. This signal processor has a clock module, through which the sailing time elapsed for each audio signal received by the hydrophone is recorded in the memory. Therefore, based on the sailing time, the exact position of the detected anomalies or leaks can be ascertained. The device is complemented by a series of external synchronisation systems, laid out every certain distance, by which the position error that could be accumulated by the device is neutralised. Thus, a simple device is attained, which is cheap, solid, durable and highly effective.

RELATED APPLICATIONS

This application is a divisional of and claims priority to and thebenefit of U.S. patent application Ser. No. 15/570,617, filed Oct. 30,2017 and entitled WATER LEAK DETECTOR DEVICE AND LEAK DETECTIONPROCEDURE, which in turn is a U.S. National Stage entry ofPCT/ES2016/070157, filed Mar. 11, 2016 and entitled WATER LEAK DETECTORDEVICE AND LEAK DETECTION PROCEDURE, the contents of which areincorporated herein by reference in their entirety.

OBJECT OF THE INVENTION

This invention relates to a device that has been specially designed todetect leaks in large diameter water pipes using low-frequency soundthat causes an anomaly in the water of a large diameter pipe in the loadsubjected to high pressures.

The object of the invention is to provide a device that, besidesallowing said detection, is reliable, simple and low-cost.

The object of the invention also includes the means to insert and removethe device, as well as the actual procedure used to detect the exactlocation of the leak.

BACKGROUND OF THE INVENTION

Concerning the scope of the practical application of the invention, incurrent water leak detection devices, particularly those focused ontransportation pipelines, the leak detection process generally uses amoisture measurement close to the water leak. This measurement iscarried out using different devices, for either measuring moisture,measuring temperature or a voltage caused by an induced current thatvaries depending on the moisture of the location.

In document U.S. Pat. No. 4,016,748 A, a method and a device to detectleaks in a pipe are presented. Starting with a fluid that flows througha pipe at a pressure above atmospheric, the method envisages the fittinginside the pipe of a floating leak sensor that is sensitive to thepressure and speed differences caused by a leak, moving the leak sensorthrough the pipe together with the fluid, with which the sensor stopsmoving once it has detected a leak.

This invention solves the first leak detection in a duct, but stops whenit is found and is relative to the size of the leak that has occurred inthe duct. Therefore, the device described in document U.S. Pat. No.4,016,748 A can be used to detect a first leak in a pipe, but it doesnot allow to detect subsequent possible leaks.

There are also leak detection devices such as those described indocument US20130186181 A1, which features a rigid body that iselastically supported within an outside cage and is moved by a suctionforce generated by a local pressure gradient arising from a leak withina pipe network. Nevertheless, this method solves the problem ofdetecting water leaks inside a pipe, but with a distance to the leakproportional to the pressure gradient generated by the leak. Thisinvention is intended to provide a solution for the entire network ofpipes through which water is transported and distributed.

Other leak detection methods based on invention patent US20140174186 Aaare also known. Said patent provides a system to detect leaks of a fluidin a pipe network using water flow meters and vibration detectors. Inthis invention, a processor analyses the signals of the flow meters. Theflow circulating through the inside of the pipe network in each sectionshould be measured. These systems are used to detect large leaks, as theflow meters must capture the flow difference between two points. If theleak is small, the value is insignificant.

Furthermore, invention U.S. Pat. No. 4,894,539 describes a method forascertaining the position of a leak in a duct or pipe, especially asmall-diameter one, in which a short piece of coax cable is inserted,which carries a short duration radioisotope into the duct or pipelineand which is forced to move throughout the piping. With this invention,leak detection is partially solved but only in small-diameter pipelines.

Trying to skirt this problem, invention patent WO 2006/081671 is wellknown. It describes a device materialised as a sort of sphere, fittedwith a magnetic sensor, an accelerometer and means for collecting data.It can include an acoustic sensor, such as a hydrophone.

By using hydrophones, i.e., by the emission of sounds and the analysisof the sounds received back by the device, as these are emitted into theinside of a pipeline, water leaks are detected in a highly effectivemanner due to the difference in response compared to a leak-free pipe.However, not only is it necessary to detect the said presence, but it isalso essential to pinpoint the exact position where the leak wasdetected.

In this sense, the device described in invention patent WO 2006/081671,provides for certain means for this purpose that are complex andexpensive, as well as inaccurate.

For this purpose and more specifically, said device has been preparedfor the sphere into which it is materialised to be fitted with featuresthat make it float for it to move by rolling through the pipe orpipelines involved. Thus, its position shall be calculated by using anaccelerometer to control the number of revolutions it spins along thewall of the pipeline. This complicates the internal structure of thedevice, in addition to obtaining a series of error-prone readings, ifthe sphere slides instead of rolling. Moreover, the risk of possiblemeasurement errors significantly increases when the length of the pipesto be analysed is very long, as there are no means to synchronise thedevice after a certain pre-established distance has been travelled.

DESCRIPTION OF THE INVENTION

The advocated device meets in a fully satisfactory manner the problemspreviously exhibited in each of the mentioned aspects, providing adevice that is much more accurate, structurally simple and morecost-effective and reliable.

To do this and based on the aforementioned conventional structuring, inother words, by including a sound sensor device, particularly with ahydrophone device and an electronic system that classifies the soundreceived by the hydrophone to univocally identify a leak in the subjectpiping, the device of the invention materialises as a sort of sphere.This sphere does not need means to make it float, insofar as it is notintended to rotate on the inner surface of the piping nor requires acoating of an adherent material that ensures said rotation. Indeed, thisdevice moves together with the flow of the circulating water through thepiping, with a neutral buoyancy. Thus, the device's sliding or rollingdoes not affect the accurate ascertaining of its position, when a leakhas been detected in the pipe.

Consequently, and as mentioned above, the device is fitted with anaquatic hydrophone associated to a signal adaptor and a processorcapable of classifying the signal received by the hydrophone. Therefore,the sound that indicates an anomaly (a water or an air pocket leak)inside a large diameter pipeline has a specific and known soundspectrum. More specifically, the sound triggered by a water leak in alarge diameter pipe under high pressures, ranges from an audible soundof between 20 Hz and 20 KHz, making it easy to differentiate andclassify. In fact, the amplitude of the sound triggered by a leak insidea large diameter pipe increases its value as the pressure increasesinside the pipe.

If there are no disturbances inside a pipe, the sounds detected inside apipe are highly likely due to an anomaly in the water of a largediameter pipeline. By fitting a hydrophone that captures this signal,when the pipe is full of water, it eliminates the need to empty thelarge diameter pipeline and fill it with gas. This also reduces thewater consumption from the emptying and filling of the water conveyanceducts.

The hydrophone and processor are attached to a battery and covered by ahollow casing. The assembly is inserted into the large diameter pipelinethrough the available access valves in the pipeline access manholes,quickly and easily.

In accordance with the essence of the invention, the microprocessor hasa clock module, which is used to assign the time elapsed since theinsertion of the device to each one of the acoustic signals received andinterpreted by it.

For the activation of this timing, the device is fitted with atriggering system through which the device starts to monitor the timeelapsed since it has been moving through the inside of the pipe, bywhich the water flow, and consequently the speed at which the deviceassembly is moving, are known.

The triggering control system is used to take the device from theswitched off mode to the switched on mode.

The device is sealed and cannot be opened. Thus, an additional connectoris required for the start up process. It consists of two main parts: aUSB connector and the control circuitry.

The USB connector is used to charge the internal battery, as well as tomake a physical connection between the internal clock module and theoutside.

The control circuitry creates a pulse that makes the device go from theon to the off mode and vice versa. It is comprised of a strip or cablethat connects the USB to the control circuitry, an ON/OFF push buttonthat generates an electric current which, in turn, makes the controlcircuitry to activate the device or not. It also includes a status LED,which signals whether it is in on or off mode.

Likewise, the device is fitted with a communication module, used to sendinformation, from inside the device to outside, without having to openit.

Information is sent in at least one of the three following manners:Bluetooth, long-range radio communication or ultrasound communication.

Bluetooth communication is used for bulk data transfers to the outside,as well as for the identification of the device.

Ultrasound communication is used to establish communication with thedevice inside the piping.

Long-range radio communication is used to establish communication withthe device if any of the other communication methods fail, it being aredundant communication system.

These means of communication of the device are extremely effective whenit comes to eliminating possible measurement errors of the device. Inthis regard, a link has been made with external synchronisation systemsevery certain distance all along the piping, through which the devicecan “reposition” and the anomalies encountered all along the tubing arecalculated.

These synchronisation systems define known reference points. Thus, thepositioning error and the uncertainty that may exist in the distancecalculation is zero at the known point.

These systems can be used to create beginning/end sections for a limitedand known travel path. By fitting them in the device's path, operabilityis improved, as greater distances can be covered, keeping a constanterror margin, allowing to minimise errors within known stretches if theyare divided into smaller ones.

For this purpose, the synchronising systems are comprised of acommunication module, a clock module and a power-supply module.

The communication module is used to send data from the device to outsidethe piping. That information can be stored in the synchronisation systemor can be sent to an external server that stores the information using aGSM/GPRS module. Communication can be one-way communication, from thesynchronisation system to the device, using beaters, tone generators andBluetooth or bi-directional communication, between the synchronisationsystem and the device, using radio or ultrasound communications.

The one-way communication system emits a pattern known to the devicefrom outside the pipe to the communication module, so that it identifiesthat pattern and acts accordingly. The pattern can be generated by abeater system, a tone generator system or a Bluetooth module.

The purpose of the device is to know the location of the anomaliesencountered inside a pipeline. To do this, audio recorded by therecording system and extracted through the start up control module isused. Using the recorded audio the anomalies inside the piping can bedetected, as well as the time that it has taken the device to reach theanomaly from the start. Once the time elapsed up to the anomaly and thewater speed are known, thanks to a series of flow meters fitted in theinsertion system, one can calculate the distance to the anomalies,thanks to the uniform rectilinear motion equation, where only thedirection of propagation of the water is taken into account.

Using only a hydrophone as a data system reduces the processing timecompared to other anomaly detection systems.

As it only takes into account the water propagation direction, theprocessing time drops, as it only has to calculate the distance based onthe time and speed.

To perform this calculation, it is necessary to know the positions (ofthe insertion system, of the extraction system, of the synchronisationsystems), the speed of the flow at the time in which device was sailingthrough the inside of the pipe and the elapsed time, since the devicewas inserted into the pipeline, up until the detection of the anomaly.

The positions are used to know the distance between the insertion,synchronisation and extraction points. To know these, the map of theplace is used. If there is no mapping, GPS is used. The points of thesynchronisation systems are used to make a calculation by stretches,reducing the error of the known stretch.

The flow speed is known thanks a flow meter fitted in the insertion orextraction system. This speed is used to know the distance based ontime, thanks to the uniform rectilinear motion equation.

To minimise error, algorithms are used to identify non-measurable statesof a dynamic system, subjected to white noise.

Furthermore, the housing may be made of different materials or a set ofthese, such as plastic. It can optionally include a wirelesscommunication module, which sends real-time sound from the inside of thepipe to a receiver communication module on the outside of the pipe.

With regards to the insertion and extraction system, an insertion deviceis defined that is comprised of a rod, a plate, an O-ring, a flexiblemetal sleeve and a flow meter.

The device is fitted inside the metal sleeve, which is connected to theinlet of the large diameter pipe. The valve of the large diameter pipeis opened and pushed into the pipe using the rod, so that the flow metermeasures the water speed.

Together with its anchorages, the metal sleeve is used to create an areawith the same pressure as that of the inside of the large diameter pipe,to which one has access. The device is inserted into this sleeve.

The rod is used to convey the movement from the upper part of thesleeve, where the device is, to the lower part of the sleeve, i.e.,inside the pipe.

The O-ring is required as the pressure inside the metal sleeve is high.Were this O-ring not used, water would come out of the joint.

The plate is required so that the device does not slip when it is pushedby the rod.

Moreover, the extraction system is used to remove the sphere from insidethe pipe under load to the outside. It is therefore made up of a metalsleeve, a rod, a net, flexible plates, a camera, an arrival detector, anO-ring and a flow meter.

For this purpose, the extraction system is fitted in a valve of thelarge diameter pipe, it is joined to the metal sleeve and it is pushedto the end of the pipe, where the plates open and the net expands.

The net traps the device when it approaches, as the camera displays itand the arrival detector is activated.

Next, the rod is pulled upwards and the device is removed from insidethe sleeve.

Likewise, the flow meter measures the water speed, an essential piece ofinformation to determine the exact distances at which the possible leaksare located.

Together with its anchorages, the metal sleeve is used to create an areawith the same pressure as that of the inside of the large diameter pipe,to which one has access.

The net is inserted into this sleeve and subsequently the device iscollected.

The rod is used to convey the movement from the upper part of thesleeve, where the extraction system is, to the lower part of the sleeve,i.e., inside the pipe. Subsequently, when the device is detected, themovement is conveyed from the inside of the pipe, where the collectionsystem is located, up to the top part of the metal sleeve, where it willbe collected.

The O-ring is used as the pressure inside the metal sleeve is high. Werethis O-ring not used, water would come out of the joint.

The camera is fitted to the lower part of the collection system, facingupwards. This allows the following actions to be performed:

1) Position the collection system in a perpendicular manner to thedirection of the pipe.2) Verify the flow circulating through the inside of the pipe, tocorroborate that the speed is sufficient to make the device sail.3) When the device reaches the collection system, to be able to see itdirectly.

The camera has a video output that is connected to an external monitoron the outside of the pipe.

The net of the collection system must be made of a material that isflexible and resistant to the blow caused by the arrival of the device.

Thus, we attain a device for leak detection in pipes that is extremelysimple, solid, effective, durable and cost-effective.

DESCRIPTION OF THE DIAGRAMS

To complement the description given below and in order to help get abetter understanding of the features of the invention, in accordancewith a preferred example of its practical implementation, attached as anintegral part of said description are a set of diagrams. By way ofexample and without limitation, they represent the following:

FIG. 1. Displays a representation of a front overhead of a water leakdetector in pipelines implemented in accordance with the object of thisinvention.

FIG. 2. Shows a view in perspective and as a cross section in accordancewith an imaginary vertical and diametric plane of the device in theprevious diagram.

FIG. 3. Shows an exploded view of the device in the previous diagrams.

FIG. 4. Displays a profile and cross section view of an access to alarge diameter pipe through which the device of the invention isinserted, showing the device used to perform the insertion in a simplemanner.

FIG. 5. Displays a view similar to that of diagram 4 but relating to theremoval means provided for the device of the invention.

FIG. 6. Displays a view of the lengthwise section of a stretch of largediameter pipe with a water leak in its wall. It can be observed thatsaid leak produces a different sound than that of the rest of the pipingwhen an acoustic signal is applied to it, which is easily identifiableby the device of the invention.

FIG. 7. Displays the perspective detail of the means of collection ofthe device, at the lower level of these.

FIG. 8. Displays the detail of the means of collection shown in diagram7, in which one can see a light-camera assembly that facilitates thetasks for the removal of said device.

PREFERENTIAL IMPLEMENTATION OF THE INVENTION

As can be seen in the reviewed diagrams and particularly in diagrams 1to 3, the device of the invention is comprised of an essentiallyspherical casing, obtained from two semi-casings (1-1′) that can becoupled and sealed between each other, within which there is ahydrophone (2), the semi-casings being fitted with holes (3) and windows(4) to which connections are fitted (7-8), connected to the hydrophone(2), in order to capture the sound that occurs in the water.

The hydrophone (2) is connected to a signal processor (9), which storesthe information on a memory card (10) and is powered by a battery (11).This signal processor (9) is fitted with a clock module (12) or timer,through which the receipt of the signals is associated with the specifictime at which they were received. Thus, from the water speed or flow,the exact location of the detected leak can be ascertained with greataccuracy, based on the time elapsed until the time of its detection.

The housing is complemented by a series of peripheral grooves into whichthe related gaskets are inserted (33). They constitute adherent mediumsthat allow the device to roll in the event of a jam. However, as hasalready been mentioned above, the means that determine the positioningof the device and, consequently, of the possible leaks, are fullyfunctional and regardless of the relative rotation position or otherwisein which the device is at the time.

These joints are in charge of increasing the drag surface so that theforce of the water moves the device. Due to having neutral buoyancy, thedevice sails through the area of the pipeline that has the highest waterspeed, that is, the centre of the pipeline.

The device can be fitted with a communication module (13), so that itcan communicate on a real-time basis with a series of synchronisationsystems, arranged externally and every certain distance all along thepiping. The communication module is used to send data from the device tooutside the pipe. Said data may be stored in the synchronisation systemor be sent to an outside server that stores the information by means ofa GSM/GPRS module.

Communication can be one-way communication, from the synchronisationsystem to the device, using beaters, tone generators and Bluetooth orbi-directional communication, between the synchronisation system and thedevice, using radio or ultrasound communication. By using saidsynchronisation systems, the positional parameters of the device arereset, preventing the accumulation of errors in the calculation of thedistance travelled by it.

Diagram 4 shows how the device is inserted into a large diameterpipeline using the access system (14) of the manholes of the waterdistribution network. In order to ensure that the leak detection systementers the pipeline (15), a rod is connected (16) with the access systemthough the access valve (17). Thus, the access valve is opened (17) andthe leak detector is pushed in using the rod (16). More specifically therod is inserted by means of its lower end through a metal sleeve (21)that is used, together with its anchorages, to create an area with thesame pressure as that of the inside of the large diameter pipe, to whichone has access.

The assembly is complemented with a non-referenced O-ring, which is usedas the inside pressure of the metal sleeve is high. Were this O-ring notused, water would come out of the joint.

To ensure the proper removal of the leak detector, diagram 5 shows adevice with a rod (16′), which has a net on its lower part (18) forreceiving the device. Similar to what occurs with the insertion device,the rod (16′) is passed through the access valve (17) of the accessinlet (14′) and is joined by means of an O-ring.

The device is complemented with a metal sleeve (21′), a couple offlexible plates (22) to which the net is attached (18) and electronicequipment (23) that includes a camera, an arrival detector and a flowmeter.

Thus, the extraction system is fitted in a large diameter pipe valve, itis joined to the metal sleeve and it is pushed to the end of the pipe,where the plates open and the net expands.

The net traps the device when it approaches, as the camera displays itand the arrival detector is activated.

Next, the rod is pulled upwards, the plates close and the device isremoved from inside the sleeve.

Likewise, the flow meter measures the water speed, an essential piece ofinformation to determine the exact distances at which the possible leaksare located.

As can be seen in diagram 6, dragged by the force of the water current(19), the leak detector system will start sailing through the pipeline(15). When a water leak is detected (20) on the wall of the piping (15),it will emit a different sound (21) that is captured by the hydrophone(2).

With regards to the dimensions of the sphere, even though these may varydue to different design criteria, as an example, it may have a radius ofbetween 50 and 150 mm and a thickness of 0.8 mm, with hermetic sealingand preferably made of plastic, although it may be made of othermaterials or combinations of these.

1. A system comprising a device for detecting water leaks in pipelines,the device comprising: a spherical casing; at least one hydrophone as areceiver of audio signals generated by mechanical signals, thehydrophone being located within the spherical casing and is connected toa signal processor, which signal processor includes a non-transitorymemory card for storage of audio information corresponding to the audiosignals received by the hydrophone and is powered by at least onebattery, the signal processor having a clock module configured to recordin the memory card sailing time elapsed for each audio signal receivedby the hydrophone and a communication module located within thespherical casing and configured to communicate on a real-time basis witha series of spaced synchronization systems residing all along thepipeline, from which the start or end of delimited and known stretchesare defined, in which there is no positioning error, eachsynchronization system being configured to reset positional parametersof the device and the device being configured to have its positionalparameters reset by each synchronization system, the synchronizationsystems comprising a communication module, a clock module and apower-supply module.
 2. A method for detecting water leaks in a pipe bya spherical water leak Detection device in the pipe, comprising: a)checking water flow through the interior of the pipe with a flow meterto confirm that a drag speed of the water flow allows the sphericalwater leak detection device to be navigated in the pipe; b) activating aclock module using an ignition control system that incorporates a USBconnector module and a control circuitry; c) inserting the sphericalwater leak detection device into the pipe by means of an insert fittingformed by a rod associated with a lower plate that has an 0-ring, aflexible metal jacket, and a flow meter; d) capturing acoustic signalswithin the pipe, along the pipe, by means of a hydrophone housed insidethe spherical water leak detection device; e) sending signalscorresponding to the captured acoustic signals by a communicationsmodule in the spherical water leak detection device; f) monitoring theposition of the spherical water leak detection device inside the pipeand repositioning the spherical water leak detection device withsynchronization systems along the pipe; g) recording in a memory insideof the spherical water leak detection device the captured signalstogether with an exact time at which each signal was captured; h)detecting arrival of the spherical water leak detection device with anarrival detector and a camera associated with an extraction accessorywhen the spherical water leak detection device approaches a net; i)removing the water leak detection device by means of the extractionaccessory, which has a rod with dimensions adapted to the diameter ofthe pipe, is associated with the net, includes an 0-ring, a metal jacketconnected with a pair of flexible plates to which the net is fixed andan electronic equipment link integrated with the camera, an arrivaldetector and a flow meter; and j) analyzing and interpreting thecaptured signals through mathematical calculations to detect possibleanomalies corresponding to possible water leaks in the pipe to obtain,from the elapsed time and the water flow that circulates inside thepipe, the exact distance in which each one of the detected anomalies isfound by means of an equation of a uniform rectilinear movement.
 3. Themethod of claim 2, wherein the detected signals are sent by bluetooth,by long-range radio communication, or by ultrasonic communication.